In memory devices, on-die-termination (ODT) may be used while Dual Inline Memory Modules (DIMMs) are being accessed, for example, during a read or a write cycle. ODT may reduce potential signal noise or interference during memory access. However, activating ODT also results in additional power consumption.
Generally, a memory controller coupled to a DIMM utilizes a channel to communicate with the DIMM. In some current designs, there may be one DIMM present for each channel. In such situations, one may use a Precharge Power Down Delay-Locked Loop (DLL) off mode only for the one DIMM per channel. However, in some computing platforms (such as server computers), there may be more than one DIMM per channel; thus, more power may be saved if any of the ranks may be placed in the Precharge Power Down DLL off (PD) state. However, when a DIMM in a multi-DIMM per channel configuration is placed in the PD state, system performance may be impacted due to asynchronous ODT operations.